Method of making unsaturated hydrocarbons



Patented Jan. 2, 194-? i i g UNITED STATES PATENT 1 METHOD or MAKINGuNsAmA'mn HYDROGARBONS Fritl- Rostler and ,Vilma Mehner, Vienna, Ger- Imany, assignors to Naftolen-Geseilschaft zur Verwertung derRostler-Mehnerschen Verfahren m. b. 11., Vienna, Germany, a corporationof Austria, now Germany.

No Drawing. Application July 21, 1938, Serial No. 220,584. In AustriaMay 4, 1932 14 claims.- (Cl. res-14s) This invention or discoveryrelates to methods oleflns, which are not desired in the purified oils.of making unsaturated hydrocarbons; and it The petroleum oil is stirredwith the acid as long comprises a method of producing new and useful asmay be desired, and the acid sludge is then oily or resinoushydrocarbons of unsaturated nasettled out and withdrawn. This sludge isa dark- 5 ture, capable of being vulcanized and otherwise colored,evil-smelling, tarry product, and is gen- 6 used, wherein acid sludgeproduced in the sulerally highly viscous, especially when heavy oilsfuric acid refining of petroleum oils is admixed are refined.

' with an excess of neutralizing agent and the ad- Various processes areknown to the prior art mixture is heated to a relatively lowtemperature, for the recovery ,of sulfuric acid from this acid 10generally below 400 C., at which it undergoes sludge; the sulfuric acidbeing recovered as such, 10

thermolytic conversion with a smooth and subor in the form of sulfurdioxide, etc. Processes stantially complete splitting into organic andinare also known for the recovery of the neutral organic portions, theorganic portion consisting oil or saturated hydrocarbons which areretained principally of the new resinous oils which are in the tar, thisbeing generally effected by dilutthen separated and recovered;separation being ing the sludge to form sludge acid and to cause eitherby extraction advantageously with a volseparation of the neutral oils.Processes have atile solvent, with subsequent distillation, or by alsobeen disclosed heretofore for recovery of the distillation at relativelylow temperatures and organic matter contained in the acid tar in theunder conditions such that the partial pressure form of asphalts and thelike. In these known so of the vapors at the point of formation is keptprior processes, it was often considered preflow, as in a' high vacuumor stream of inert gas; erable to treat mixtures of acid tars, or acidtars the oily product in any case being distilled at a and sludges inadmixture with other lay-products. temperature such that cracking anddecomposi- It is our discovery that acid sludges, upon suittion aresubstantially avoided; and our invention able treatment, yield as aproduct a new type of further comprises, as new and useful materials,oily unsaturated hydrocarbons having distinctive 25 the oily, orresinous, hydrocarbon distillates obproperties. These new products maybe obtained tained by thermolytic conversion of over-neufromsubstantially any of the acid tars or sludges tralized acid sludge, saiddistillates being high obtained by refining mineral oils and theirfracboiling viscous liquids or resinous solidsat orditions with sulfuricacid; and it is immaterial 3o nary temperatures, having a reddish browncolor whether the sludge is produced in refining parafwith greenfluorescence, being soluble in acetone, finic or naphthenic mineral oilproducts. Reaniline and concentrated sulfuric acid, and being gardlessof the source, we always obtain unsatuvulcanizable and readily preparedin a condition rated hydrocarbons which are soluble in concenfree ofrubber poisons; all as more fully 'hereintrated sulfuric acid and havehigh molecular after set forth and as claimed. weight and highviscosity. In some respects, 35

The treatment of petroleum oils, including these new products resembleoily resins or resinfractions thereof, with sulfuric acid,- results inous oils. the formation of reaction products which remain While acidsludges are obtained in the refining associated with the unconsumed acidas a viscous of both cracked and uncracked petroleum prod- 40 liquid orsemi-solid material. This material is ucts, it is known that thesesludges and their 40 known variously in this country as petroleum acidconstituents differ somewhat in composition and sludge, refinery acidsludge, sulfuric acid sludge, properties. In our invention, the acidsludges or acid sludge; and abroad; it is generally desigproduced inrefining natural oils, or fractions nated "acid tar. As stated, thepresent invenobtained in the low pressure distillation thereof,

tion relates to the production of unsaturated are most desirable. Inother words, our inven- 45 hydrocarbon products of a particular type,soluble tion is best applied to the acid sludges obtained inconcentrated sulfuric acid and having other in refining uncrackedpetroleum oils and proddistinguishing characteristics, from these aciducts. The sludges formed in refining cracked tars or acid sludges. Thisapplication is a conpetroleum products, and especially crackedgastinuation-in-part of our copending applications, olines and otherlight products, are not well 50 Serial No. 751,891, filed November '7,1934, and Sesuited for treatment in accordance with our rial No.138,666, filed April 23, 1937. invention, and yield different and lessdesirable In refining mineral oils with sulfuric acid, the products whenso treated. acid withdraws from the oil unsaturated organic Our newhydrocarbon products are best obcompounds of various types, includingresins and tained when utilizing'acid tars or sludges which 5| have beenpreviously freed from neutral oil, as by centrifuging, etc. When neutraloils are present in the sludge, they go forward with the distillateproduced in accordance with our invention, and the distillate is admixedor diluted with neutral or saturated hydrocarbons to that extent. Wefind it more advantageous to use as a raw material an acid sludge whichhas been previously freed from neutral oil.

We have found that the tarry constituents of the sludge consist mainlyof addition products of sulfuric acid and the unsaturated organiccompounds present, and we have also found that oily hydrocarbons whichare soluble in sulfuric acid, and which have the other distinctiveproperties mentioned herein, may be recovered from these tarryconstituents of the sludge by gentle treatment. It is a necessary partof the treatment to split on the combined sulfuric acid, and toeliminate it from the product along with substances having an undesiredpolymerizing effect, such as free acid or metallic halides such asaluminum chloride. It is our discovery that this may be accomplished byadding to the sludge more than enough neutralizing material to combineall the acid present'in free form, and also that in combination withorganic compounds,

and then gently heating the mixture to cause thermolytic conversion intoan organic portion constituting our new'hydrocarbon product and aninorganic portion containing all the acidic, basic, and other inorganicconstituents of the mixture. The hydrocarbon or oily portion may beseparated from the mixture as fast as it is formed, as by distillationunder suitable conditions described hereinbelow; or it may be separatedafter conversion is complete, as by extraction and fractionation of theextract. In all cases, the sulfuric acid and other inorganicconstituents of the acid sludge are separated from the hydrocarbonproduct and left in the residue of distillation or extraction, alongwith the excess neutralizing'agent; and this residue obtained in ourprocess contains such a small proportion of organic material that it isnot suitable for use as fuel, The organic constituents of the acid tarare, however, substantially completely converted into the newunsaturated hydrocarbon product. In other words, our process convertsthe acid sludge into an unsaturated hydrocarbon distillate and anon-volatile, inorganic residue.

It is thus an object achieved by our invention to provide a method forproducing useful, new, unsaturated hydrocarbon products from the acidsludges produced in refining mineral oils. Another object achieved byour invention is to provide these new unsaturated hydrocarbon products,which have many applications in the arts.

In the operation of our process, we mix with the acid sludge a quantityof neutralizing agent which is suflicient to bind not only any free acidpresent, but also any acid which may be released by its organicassociates during the thermal treatment. There is thus no undesiredpolymerizing action during distillation, or during any other step of theprocess; or, if polymerization occurs, it does not result in undesirablesaturated compounds. As a rule, we determine analytically the totalsulfur content of the acid sludge to be treated, and we then employ moreneutralizing agent than corresponds to the total sulfur calculated as803. This excess of neutralizing agent serves under all conditions tobind any acid which might otherwise be released during any stage of theformation and recovery of the new products, and thus preventspolymerization to saturated compounds and other undesired actions. It isessential to have an excess of neutralizing agent present and availableduring any heating of the unseparated reaction mixture.

We may use as neutralizing agents metal oxides or hydroxides or suitablesalts such as carbonates, and we may also use metals which are readilyattacked by the acid which is present or liberated in the mixture. Whenusing metals, gases are developed which have the advantageous effect ofloosening up the mixture, while the metal present improves heattransfer. Metallic wastes, such as turnings or metal chips. are suitableneutralizing agents. The loosening efiect is, of course, also obtainedwhen using as neutralizing agents carbonates, etc., which also evolvegases. Whatever neutralizing agent may be employed, it is essential thatit be employed in excess.

We have found that certain compounds catalyze the reaction between theacid sludge and the neutralizing agent and shorten the time required forits completion. These catalytic agents also improve the yield and thequality of the organic reaction product (the new hydrocarbons) obtained.Catalysts which we have found to have this efl'ect are heavy metal saltssuch as copper sulfate and iron sulfate. These catalysts may be added tothe neutralizing agent or to the mixture of neutralizing agent and acidsludge. When using slaked lime as the neutralizing agent, the catalystmay conveniently be incorporated therein by slaking with a coppersulfate solution. Some commercial products contain sumcient iron orcopper compounds as impurities.

to make the use of additional catalysts unnecessary. This is often trueof dolomite, for example, which is a suitable neutralizing agent for ourprocess. I

The reaction mixture obtained by combining the acid sludge and excessneutralizing agent is substantially solid at ordinary temperatures andmay be comminuted, if desired, prior to distillation. Dry distillationis then effected, generally in a vacuum, as this makes possible the useof lower temperatures. In any case, it is best to so operate that thehighest temperature, even at the end of the distillation, does notexceed 380 C. It may sometimes be permissible to end at a temperature ashigh as 410 C., but it is better to remain below 400 C., and we regardit as best to maintain the hydrocarbons at temperatures below 360 C. atall stages of the treatment. In practice, it is often permissible tooperate at even lower temperatures, as shown by the exampleshereinbelow. The use of temperatures below about 400 C. preventscracking and decomposition or other undesired effects on the unsaturatedhydrocarbons which are desired in the product.

One method of separating the desired hydrocarbon products from thereaction mixture by distillation at these low temperatures, is tooperate under a rather high vacuum. When so operating, the pressureduring distillation should not exceed 100 mm. mercury, and, in practice,is often as low as 12 to mm. or less. This effects a .low partialpressure of the oil (hydrocarbon) vapors at the point of evolution. Whenrelying on vacuum to eifect this low partial pressure, it is necessaryto employ greatly reduced pressure in the still, and it is dimcult orimpossible to obtain our unsaturated hydrocarbons if the pressure duringdistillation exceeds 100 mm. mercury. At higher pressures, in thismethod of operating, the unsaturated hydrocarbons constituting our newproduct are not separated as such from the mixture, or are 'partiallyconsumed (oxidized) by the sulfuric acid constituents present, or areotherwise changed into undesirable products, in whole or in part.

It is often advantageous, when operating under high vacuum, to apply thevacuum for a time at a certain temperature-say 200 C.-and then to shutofi the vacuum while rapidly raising the temperature to 250 C., forexample. This stepwise operation may be repeated as often as de sired,and eflects considerable saving of time as compared with operatingentirely under vacuum. The vacuum distillation may be eflected whilepassing through the still a current of an inert gas, such as superheatedsteam. V of inert gas during the dry vacuum distillation shortens thetime required for complete recovery of the hydrocarbon distillate, andhas the further advantage that it permits treatment under even moregentle conditions than the vacuum alone.

In another embodiment of our invention, the essential low partialpressure of the oil vapors at the point of evolution is insured by thecirculation of a substantial current of inert gas through the still.This is effective in obtaining the desired products when no vacuum isapplied, or when there is a slight vacuum not sufllcient in itself toenable operation at the desired low temperatures. For example, the dryreaction mixture may be fed through a tubular chamber equipped with ahelical conveyor. The chamber and the reaction product therein areheated to a temperature of the order of, but not exceeding, 400 C., anda current of nitrogen or other inert gas is passed through the chamber,advantageously countercurrent to the movement of the reaction material.This produces in the chamber an atmosphere consisting predominantly ofthe inert gas, and reduces the partial pressure of the evolvedhydrocarbon vapors. The vapors are carried out of the chamber with thegaseous current and readily condensed therefrom by cooling in knownmanner. Advantageously, the gas partially or completely stripped of oilvapors is then reheated, as by a heat exchanger and auxiliary heater,and returned to the chamber. Re-

circulation is desirable as it minimizes loss of heat, as well as lossof the product, from the system.

This embodiment of our invention may also be operated on a batch basis,although it is advantageous to operate it on a continuous basis withrecirculation of the gas and heat exchange between gas withdrawn fromthe stripping chamber and'gas returned thereto. In this method ofoperation, as well as when operating at a high vacuum, the newhydrocarbon product may be obtained at sufiiciently low temperatures toinsure the desired characteristics.

The embodiments of our process described hereinabove include treatmentof acid sludge from the sulfuric acid refining of mineral oil with anexcess of neutralizing agent, with or without the presence of neutraloil, followed by dry distillation of the organic reaction product atrelatively low temperatures and conditions of low partial pressure. In amodification of these methods, the mixture, of acid sludge and theexcess of neutralizing agent is treated with a suitable organic solventfor the hydrocarbon compounds, advantageously after heating suflicientlyto effect thermolytic conversion into the desired hydrocarbon productand the substantially inorganic residue. Suitable solvents includeether, acetone and other ketones, liquid hydrocarbons and chlorinatedhydrocarbons. These solvents extract the desired oily or resinousunsaturated hydrocarbons from the reaction mixture, and the extract thusobtained is subiected to distillation. Advantageously, this distillationof the extract is effected under reduced pressure, with a fractionationof the distillate to recover the solvent for re-use. This vacuumdistillation of the extracts may be accompanied by a feed of an inertgas, as previously described, and neutralizing agents should be presentthroughout the distillation. Extraction effects a pre-purification ofthe product, and the hydrocarbons recovered by this treatment are morepure than those obtained without extraction. Extraction also facilitatesdistillation of the product. When an end product of extremely highpurity is required, the product of the original distillation of eitherthe extract or the reaction mixtures may be redistilled.

In a modification of the extraction process, the extract obtained ismerely heated to distill oi! the volatile solvent. The residue consistsof our new hydrocarbons in sufllcient purity for some applications.

The hydrocarbon product obtained according to our invention consists ofunsaturated compounds having a composition, determined by analysis, ofapproximately 90 per cent carbon and 10 per cent hydrogen. Thiscorresponds to the general formula (Cal-I4). The molecular weight ofthese products varies from about 400 to 1000. and usually averagesapproximately 600. They have a. reddish brown color and a greenopalescence or fluorescence, and may be oils of high viscosity orresin-like substances at ordinary temperatures. Their specific gravitiesare high, being, as a rule, greater than one. Their boiling points aremuch higher than those of the petroleumdistillates from which the acidsludge was obtained; as a rule, they distill over at temperaturesbetween 160 and 380 C. at a pressure of 12 mm. mercury. Theirviscosities at ordinary temperatures are often 100 to 200 times as highas those of the refined mineral oil products from which they areobtained. Their iodine numbers are low, often below 20.

These new hydrocarbon products are still further distinguished fromother hydrocarbons of mineral origin by their reactions with variousreagents. They react but slightly, if at all, with dilute aqueousreagents, but they are extremely reactive with several concentratedreagents. They can be nitrated smoothly, forming derivatives ontreatment with strong nitric acid; and on treatment with strong sulfuricacid they are converted into addition products with considerableevolution of heat. In contrast with ordinary petroleum hydrocarbons,they are completely soluble in acetone and aniline, as well asconcentrated sulfuric acid. Hydrogenation under conditions usuallysuitable for mineral oils is so diihcult as to be impractical. They havea great affinity for sulfur, however, and, when heated with smallquantities of sulfur, they form more highly viscous derivatives orpolymerization products. It thus appears that they are closely allied torubber, (CsHaM; and, like rubber, they are vulcanizable.

We have thus obtained a new and definite type of unsaturatedhydrocarbons, having distinctive reactivities, from the acid sludgesproduced in refining mineral oil products with sulfuric acid. Our newhydrocarbon product is entirely distinct from products obtained in priorprocesses of treating acid sludge or acid tar. These prior products wereeither mixtures of previously known hydrocarbons, such as benzines andlubricating oils, or products such as asphalts, having no definitecomposition. Furthermore, while the prior products varied greatly inaccordance with the starting material. the characteristics of our newproduct are substantially independent of the starting material.

The peculiar properties ofour new oils and their availability in largequantities make them useful in numerous branches of the chemicalindustry. For example, they may be used as slowly resinifying oils forimpregnation; and they, or their nitric acid derivatives, may be used inthe production of lacquers and varnishes. They also find manyapplications in the rubber industry, where they are useful as filling orspreading materials, in devulcanization" and regeneration, and for otherpurposes described in detail in our co-pending applications, Serial No.166,392, filed September 29, 1937, and Serial No. 263,810, filed March23, 1939.

When the acid sludge used as a starting material in our process isobtained by refining solid parafiin with sulfuric acid, the product ofour distillation generally contains saturated hydrocarbons (paraifins)which are insoluble in sulfuric acid, along with the desired unsaturatedhydrocarbons which are soluble in sulfuric acid. Our unsaturatedhydrocarbon product may then be separated from the parafiin by treatmentwith a suitable selective solvent, such as acetone or ether-alcohol, orotherwise.

Various embodiments of our invention are illustrated in the followingexamples:

Example I.A mixture of 30 parts of acid sludge, obtained in refininglubricating oil with sulfuric acid, and of parts pulverized chalk, wassubjected to distillation in vacuo. There resulted a reddish brownfluorescent oil in a yield of 27 per cent on the acid sludge. -Most ofthe distillate was obtained between 270 and 290 C. under a pressure of12 mm. mercury. It was completely soluble in concentrated sulfuric acid.

Example II.--38 parts of acid tar obtained in refining a lightlubricating oil were mixed with 40 parts chalk, and the mixture wasdistilled in vacuo. The distillation produced a highly viscous oil, mostof which came over between 250 and 270 C. at a pressure of 12 mm.mercury. The yield was 34 per cent on the acid sludge, and the productwas soluble in sulfuric acid.

Example III. 50 parts of acid sludge from paraflln refining were mixedwith 30 parts chalk and distilled in vacuo. There was obtained a lightyellow parafiln-like mass. This was extracted with acetone to recoverhydrocarbons soluble in sulfuric acid, amounting to 5 per cent on theacid sludge. Paraffin was also recovered in a yield of 30 per cent onthe sludge.

Example IV.-100 parts of centrifuged acid sludge obtained in therefining of automobile oil were mixed with 60 parts magnesite. Themixture was pulverized and distilled in vacuo. The distillate boiledbetween 175 and 320 C. at a pressure of 40 mm. mercury. The yield ofhydrocarbons soluble in sulfuric acid amounted to 40 per cent on theacid tar.

Examp e V.-100 parts of an acid resin obtained by refining petroleumwith sulfuric acid and drawn from an acid tar pit where it had 9,1ss,osa

'lime and distilled in vacuo with superheated steam. ()il soluble insulfuric acid was obtained in a yield of per cent on the acid tar.

Example VIII.10 parts of acid sludge obtained in the refining oflubricating oil were mixed with 4 parts copper chips and distilled invacuo. The yield of hydrocarbons soluble in 'sulfuric acid was 28 percent on the acid sludge.

Example IX.-100 parts of acid sludge, obtained by refining lubricatingoil in a process employing De Laval separators, were reacted with 60parts iron chips and distilled in vacuo. The distillate was obtained attemperatures between 185" and 340 C. at a pressure of 60 mm. mercury.Hydrocarbons soluble in sulfuric acid were obtained in a yield of 40 percent on the acid tar.

Example X.100 parts acid sludge from refining paramn were mixed with 70parts chalk and 2 parts iron chips. The reaction product was extractedwith ether and the extract was distilled in a vacuum of 12 to 40 mm.mercury over calcium oxide. The maximum temperature was 380 C. The yieldwas 30 parts parafiin and 5 parts of oil soluble in sulfuric acid.

Example XI.100 parts of acid tar, obtained in refining lubricating oil,were mixed with 80 parts of slaked lime containing copper, added by theuse of copper sulfate solution in slaking. The reaction mixture wassubjected to dry distillation in vacuo, and resulted in 60 parts of veryviscous oil and traces of paraffin.

Example XlL-lOO parts of acid sludge from parafiln refining were heatedwith 60 parts of lime, and the product obtained was mixed with cuttingsof brass wire gauze and distilled in vacuo. The yield was parts parafilnand 10 parts of oil soluble in sulfuric acid.

Example XIII.--100 parts of acid sludge derived from parafiin refiningwere mixed with 2 parts of iron filings and '70 parts of lime. Afterheating, the reaction mixture was extracted with acetone oil. The yieldobtained after removal of the acetone oil was 20 parts paraflin and 5parts of oil soluble in sulfuric acid.

Example XIV.100 parts of acid sludge derived from refining lubricatingoil were mixed with 60 parts lime. The dry mixture was charged into aninclined tubular chamber provided with a helical conveyor through whicha countercurrent of nitrogen was recirculated. The chamber wasmaintained at a temperature of 350 to 390 C. Gas and vapors dischargedfrom the chamber were cooled to a temperature of 120 0., condensing thehydrocarbon product from the gas stream before returning the nitrogen tothe chamber. The yield was 42 per cent, calculated on the acid sludge,of oil soluble in sulfuric acid.

The parts mentioned in the above examples are parts by weight. Theseexamples are given by way of illustration only, and not by way oflimitation, and various modifications may be made in the detailsdisclosed therein without departing from the spirit of our invention.

While, as stated hereinabove, any acid sludges from the refining ofpetroleum oils may be used, the most useful products for mostapplications now known are obtained only from the sludges derived frompetroleum oils heavier than kerosene. Of these, we generally find acidsludges from lubricating oil refining the most suitable.

In the embodiment of our process wherein a current of gas is employed tomaintain low partial pressure of the hydrocarbon vapors, the gas currentalso removes the vapors substantially as fast as they are produced.Other inert gases besides nitrogen may be used for this purpose. Air hasan oxidizing effect which is undesirable, but products of combustion aresubstantially free from this objection. Steam works well, but its use isexpensive in heat units. It is not necessary, however, to completelycondense the oils from the gas stream when the gas is recirculated, asthe uncondensed hydrocarbons are not lost from the system.

The product resulting from the process of this application is fm'therdescribed and claimed in our copending divisional application, Serial'No. 275,726, filed May 25, 1939.

What we claim is:

1. The method of producing new and valuable unsaturated hydrocarbons,which comprises mixing acid sludge from the sulfuric acid refining ofpetroleum oils with an inorganic alkaline reagent selected from thegroup consisting of oxides, hydroxides and carbonates of alkali andalkali earth metals, said reagent being employed in a quantity in excessof that required to combine with all of the sulfur present in thesludge, calculated as $03, heating the mixture to efi'ect thermolyticconversion into a substantially inorganic non-volatile fraction and anunsaturated hydrocarbon fraction, recovering said hydrocarbon fractionfrom the reaction mixture by a procedure including distillation underconditions of low partial pressure, and keeping the temperature of thesaid hydrocarbon fraction in the range below about 360 C. throughout theprocess.

2. The method of claim 1, wherein recovery of said hydrocarbon fractionis effected by distillation substantially as fast as formed, whilemaintaining such low partial pressure of the hydrocarbon at the point offormation that its boiling range is below 360 C.

3. The method of claim 1, wherein recovery of said hydrocarbon fractionis effected by distillation substantially as fast as formed. whilemaintaining low partial pressure of the hydrocarbon at the point offormation by application of a vacuum to the distilling chamber.

4. The method of claim 1, wherein recovery of 1 said hydrocarbonfraction is eflected by distillation substantially as fast as formed,while maintaining low partial pressure of the hydrocarbon at the pointof formation by circulating inert gas through the distilling chamber.

5. The method of claim 1, wherein recovery of said hydrocarbon fractionis effected by distillation ata rate substantiauy as fast as it isformed while maintaining low partial pressure of the hydrocarbon at thepoint of formation by application of a vacuum to the distilling chamberwhile passing a small amount of inert gas therethrough.

6. The method of'claim 1, wherein recovery of said hydrocarbon fractionis effected by extraction of the reaction mixture with a volatileorganic solvent to form an extract, which is then distilled to separatethe hydrocarbon, and wherein the hydrocarbon is distilled under vacuum.

'7. The method of claim 1, wherein the neutralizing agent compriseslime.

8. The method of claim 1, wherein the neutralizing agent is dolomite.

9. Process for the production of viscous hydrocarbon products which.consists in mixing acid tar prepared from mineral oils by sulfuric acidrefining with dolomite in sufiicient quantity to split oif andneutralize the chemically combined acid and prevent polymerization ofthe resulting unsaturated hydrocarbon and to leave an excess of theneutralizing agent, followed by vacuum distillation of the mixture inthe presence of the excess neutralizing agent and collection of thehydrocarbon distillate.

10. Proces for the production of viscous hydrocarbon products whichconsists in mixing acid tar prepared from mineral oils by sulfuric acidrefining with dolomite in sufficient quantity to split off andneutralize the chemically combined acid and prevent polymerization ofresulting unsaturated hydrocarbon and to leave an excess of theneutralizing agent, followed by the addition of a catalyst selected fromthe group consisting of iron, copper and brass and vacuum distillationof the mixture in the presence of the excess neutralizing agent andcollection of the hydrocarbon distillate.

11. In the manufacture of new and useful unsaturated oils of highmolecular weight, low iodine number and high boiling point from wastepetroleum acid sludge, the process which comprises mixing such sludgewith an inorganic alkaline reagent selected from the group consisting ofoxides, hydroxides and carbonates of alkali and alkali earth metals,said reagent being employed in a sufilcient amount to form a dry basicmass, heating the mass to a temperature under the cracking temperatureof the oils to be produced, thereby producing internal molecularreactions of the nature of thermolysis with scission. of the organic andinorganic constituents. the organic constituents being said new andvaluable oils, and recovering the new oils from the thermolyzed reactionmixture, the temperatures of the said new oils being maintained in therange below about 360 0. throughout the process.

12. The method of claim' 11, wherein the acid sludge is freed fromentrained neutral oils before mixture with the alkaline reagent.

13. The method of claim 11, wherein the said acid sludge is obtained inthe refining of petroleum oils heavier than kerosene.

14. The method of claim 11, wherein heating of the mixture of acidsludge and neutralizing agent-is effected in. the presence of acatalyst.

FRITZ ROSIE-ER. VILMA

